Web开发实战：jsp、userBean与setProperty教程-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_64938628/article/details/124143264

新建带xml的Web项目：

首先右键新建项目

然后

建好的xml在WEB-INF文件里

常用jsp标签(自带):

1.<jsp:include page="页面"> 包含
2.<jsp:param name="name" value="va"> 传参
3.<jsp:foward page="页面"> 转发
4.<jsp:useBean>相当于实例化类
5.<jsp:setProperty>给useBean属性设置值
6.<jsp:getProperty>取值

userBean用法：

<jsp:useBean id="" beanName="" type="" class="" scope="">

id: 对象名
class:类创建对象时,完全限定名(包名+类名)
type:类型调用对象时 (可以用抽象父类或者接口)
scope:作用域 (page request session application)

setProperty用法：

<jsp:setProperty name="" property="" value="">

name:useBean 的id
property:属性名(要注意必须跟实体类中的属性名保持一致)
value:属性值

接下来我们运用一下jsp标签

案例

登陆界面代码

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>啦啦啦</h1>
<!-- 
         type：
                  1.热门商品
                  2.猜你喜欢
                  3.折扣商品
 -->
<!--包含主页面的值-->
<jsp:include page="index.jsp">
          <jsp:param value="1" name="type"/>
</jsp:include>
<jsp:include page="index.jsp">
          <jsp:param value="2" name="type"/>
</jsp:include>
<jsp:include page="index.jsp">
          <jsp:param value="3" name="type"/>
</jsp:include>
<!-- html注释 -->
<%--java注释 --%>
<%--必须用java注释
<jsp:forward page="index.jsp"/>
 --%>
 <form action="dologin.jsp">
             <input name="id"><br>
             <input name="username"><br>
             <input name="password"><br>
             <button>登录</button>
             
 </form>
</body>
</html>

主页面代码

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style >
        
        .h1{
        border: 10px solid red;
        height: 200px;
        }
        
</style>
</head>
<body>
<%
        String type=request.getParameter("type");    
        String data="";
        if("1".equals(type)){
        	data="热门商品";
        }
        if("2".equals(type)){
        	data="猜你喜欢";
        }
        if("3".equals(type)){
        	data="折扣商品";
        }
%>
<h1 class="h1"><%=data %></h1>
</body>
</html>

写一个pojo包，建一个User类，记得导jar包

package com.zking.pojo;

public class User {
         private Integer id;
         private String username;
         private String password;
		public Integer getId() {
			return id;
		}
		public void setId(Integer id) {
			this.id = id;
		}
		public String getUsername() {
			return username;
		}
		public void setUsername(String username) {
			this.username = username;
		}
		public String getPassword() {
			return password;
		}
		public void setPassword(String password) {
			this.password = password;
		}
         
         public User() {
			// TODO Auto-generated constructor stub
		}
		public User(Integer id, String username, String password) {
			super();
			this.id = id;
			this.username = username;
			this.password = password;
		}
		@Override
		public String toString() {
			return "User [id=" + id + ", username=" + username + ", password=" + password + "]";
		}
        
}

处理登陆代码

<%@page import="com.zking.pojo.User"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%
        User user=new User();
         user.setId(1);
         user.getId();
%>
<jsp:useBean id="u" class="com.zking.pojo.User"></jsp:useBean>
<jsp:setProperty property="id" name="u" param="id" />
<jsp:setProperty property="username" name="u" param="username" />
<jsp:setProperty property="password" name="u" param="password"/>
<jsp:getProperty property="username" name="u" />
<%
          u.getId(); 
          out.print(u);
%>

xml代码

记住修改了xml原来代码，一定要重启服务器

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" id="WebApp_ID" version="4.0">
  <display-name>Web13</display-name>
  <!--web.xml如果被修改，服务器必须重启  -->
  <welcome-file-list>
    <welcome-file>login.jsp</welcome-file>
  </welcome-file-list>
</web-app>

今天就到这了，拜拜ヽ(✿ﾟ▽ﾟ)ノ。